Relaxation et décohérence des polarons dans les boîtes quantiques de semi-conducteurs

Abstract : This thesis presents a theoretical study of electron-phonon interaction in InAs/GaAs quantum dots, where the strong coupling regime between confined carriers and optical phonons leads to entangled states known as polarons.
Firstly, we take into account the strong coupling between exciton and optical phonons in order to calculate interband magneto-absorption.
Secondly we calculate the lifetime of polaron states. Their instability is shown to be triggered by their phonon component. We demonstrate the need to take into account the different anharmonic processus, their efficiency being very sensitive to the polaron energy. These calculations allow to explain the non-monotonous variation of the measured polaron lifetime as a function of their energy.
Then we study the spin-flip processus between singlet and triplet states in doubly charged quantum dots, by taking into account spin-orbit interaction in addition to electron-phonon couplings.
Finally we study the coherence of the fundamental intraband transition. The thermal broadning of this transition is shown to be due to real and vritaul transition towards the second excited level.
Document type :
Theses
Physics. Université Pierre et Marie Curie - Paris VI, 2008. French


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Contributor : Thomas Grange <>
Submitted on : Wednesday, October 22, 2008 - 5:53:36 PM
Last modification on : Thursday, October 21, 2010 - 11:08:09 AM

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  • HAL Id : tel-00333256, version 1

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Thomas Grange. Relaxation et décohérence des polarons dans les boîtes quantiques de semi-conducteurs. Physics. Université Pierre et Marie Curie - Paris VI, 2008. French. <tel-00333256>

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